Integrated circuit with a pressure sensor

• US 10,060,817 B2
• Filed: 09/07/2016
• Issued: 08/28/2018
• Est. Priority Date: 06/12/2012
• Status: Active Grant

• Current Assignee: ams AG (Ams-Osram AG)
• Original Assignee: ams AG (Ams-Osram AG)
• Inventors: Nackaerts, Axel, Besling, Willem Frederik Adrianus, Reimann, Klaus
• Primary Examiner(s): Tran, Dzung
• Application Number:
  US15/258,988
• Publication Number:
  US 20160377497A1
• Time in Patent Office: 720 Days
• Field of Search: 257415
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 7/008 MEMS characterised by an electronic circuit specially adapted for controlling or driving the same B81B7/0087 takes precedence; arrangements for starting, regulating, braking, or otherwise controlling an actuator H02N; control arrangements or circuits for visual indicators G09G3/00
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
• CPC Class Codes: B81C 2203/0771 Stacking the electronic processing unit and the micromechanical structure
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: H01L 21/28 Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268 etching for patterning the electrodes H01L21/311, H01L21/3213; multistep manufacturing processes for data storage electrodes H01L29/4011
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure

Abstract

Disclosed is an integrated circuit, comprising a semiconductor substrate carrying a plurality of circuit elements; and a pressure sensor including a cavity on said semiconductor substrate, said cavity comprising a pair of electrodes laterally separated from each other; and a flexible membrane over and spatially separated from said electrodes such that said membrane interferes with a fringe field between said electrodes, said membrane comprising at least one aperture. A method of manufacturing such an IC is also disclosed.

Claims

1. An integrated circuit, comprising:

a semiconductor substrate carrying a plurality of circuit elements;

a pressure sensor including a cavity on the semiconductor substrate,

wherein the cavity comprises a pair of electrodes laterally separated from each other, and a flexible membrane spatially separated from the electrodes such that the membrane interferes with a fringe field between the electrodes, and

wherein the flexible membrane comprises tungsten as a metal layer having at least one aperture and a capping layer filling the at least one aperture and being silicon nitride; and

a metallization stack comprising at least one patterned metallization layer for interconnecting the plurality of circuit elements and a passivation layer over the at least one patterned metallization layer,

wherein the electrodes of the pair of electrodes are at least partially located on the passivation layer and are conductively coupled to portions of the at least one patterned metallization layer by vias extending through the passivation layer.

2. The integrated circuit of claim 1, wherein the electrodes are interdigitated electrodes.

3. An integrated circuit, comprising:

a semiconductor substrate carrying a plurality of circuit elements;

a pressure sensor including a cavity on the semiconductor substrate,

wherein the cavity comprises a pair of electrodes laterally separated from each other, and a flexible membrane spatially separated from the electrodes such that the membrane interferes with a fringe field between the electrodes, and

wherein the flexible membrane comprises a conductive layer that is connected to ground and shields the pair of electrodes from external fields; and

an interconnect layer underneath the pair of electrodes,

wherein the interconnect layer is grounded and protects the pressure sensor from external influences,

wherein the electrodes comprise an electrically insulating film on the surface facing the flexible membrane, and

wherein the material of the insulating film is silicon-rich silicon nitride or aluminum oxide.

4. The integrated circuit of claim 3, wherein the semiconductor substrate is grounded.

5. An integrated circuit, comprising:

a semiconductor substrate carrying a plurality of circuit elements;

a pressure sensor including a cavity on the semiconductor substrate,

wherein the cavity comprises a pair of electrodes laterally separated from each other, and a flexible membrane spatially separated from the electrodes such that the membrane interferes with a fringe field between the electrodes;

one or more trenches defining a guard around the cavity,

wherein the trenches are filled with a conductive material,

wherein the flexible membrane comprises tungsten, and

wherein the one or more trenches are filled with tungsten; and

a metallization stack comprising at least one patterned metallization layer for interconnecting the plurality of circuit elements and a passivation layer over the at least one patterned metallization layer,

wherein the electrodes of the pair of electrodes are at least partially located on the passivation layer and are conductively coupled to portions of the at least one patterned metallization layer by vias extending through the passivation layer.

6. The integrated circuit of claim 5, wherein the guard is realized as a guard ring around the cavity.

7. An integrated circuit, comprising:

a semiconductor substrate carrying a plurality of circuit elements; and

a pressure sensor including a cavity on the semiconductor substrate,

wherein the cavity comprises a pair of electrodes laterally separated from each other, and a flexible membrane spatially separated from the electrodes such that the membrane interferes with a fringe field between the electrodes,

wherein at least some of the plurality of circuit elements define a capacitance measurement circuit,

wherein the electrodes are conductively coupled to the capacitance measurement circuit that comprises a sigma/delta capacitance-to-digital converter,

wherein the electrodes form capacitor plates,

wherein the electrodes realize a fringing field capacitor,

wherein the membrane is not used as one of the capacitor plates,

wherein the electrodes comprise an electrically insulating film on the surface facing the flexible membrane, and

wherein the material of the insulating film is silicon-rich silicon nitride or aluminum oxide.